As a provirus, HIV DNA transcription results in a single full-length message, which through splicing events encodes 9 different genes. The switch from early gene expression (fully spliced transcripts) to late gene expression (singly and non-spliced transcript; structural and enzymatic genes) is dependent on the expression of HIV Rev. Rev prevents the full splicing of HIV transcript. We have constructed a Rev-dependent expression vector, composed of 4 segments of the HIV genome, as well as an open reading frame that encodes any gene of interest. In our initial work we have utilized reporter genes in the construct. As the reporter expression is dependent on HIV Rev expression, the generation of reporter defines the presence of HIV infection. We have made two reporter cell lines. One cell line, derived from the human T cell CEM, is infected by all HIV-1 tested to date, including both T cell and macrophage tropic HIV-1, as well as HIV-2. This permits measurements of infectivity over a wide range of HIV isolates. We have also constructed a lentivirus that reports the presence of HIV in live cells and tissues. We have found that this reporter lentivirus identifies the presence of HIV in mixed populations of primary terminally differentiated human macrophages. Although our cell and lentiviral constructs have involved reporters such as green fluorescent protein and beta-galactosidase, the choice of other genes presents other diagnostic and therapeutic options.